人白血病细胞株重组激活基因表达及T细胞受体基因重排的检测

背景：淋巴细胞特异性重组激活基因编码的重组激活基因1与重组激活基因2蛋白是参与V（D）J重排机制的重要的重组酶。除参与V（D）J重排以外，近年的研究结果表明重组激活基因介导的转位作用可能与染色体易位及淋巴性恶性肿瘤的发生有关，但迄今尚未有明确定论。目的：检测重组激活基因、DNA修复因子Ku70／Ku80和末端脱氧核苷转移酶mRNA表达以及T细胞受体基因重排在人白血病和淋巴癌细胞株的发生情况。设计：重复测量实验。单位：南方医科大学生物技术学院分子免疫研究所。材料：T淋巴白血病细胞株Jurkat和6T-CEM购自上海细胞生物研究所；T淋巴白血病细胞株Molt-4，皮肤T细胞淋巴癌细胞株HuT102，Burkitt’s淋巴癌细胞株Raji和Daudi以及原髓细胞白血病细胞株HL-60和慢性髓原白血病细胞株K562均由本实验室保存。细胞用含有体积分数0．1胎牛血清的RPMI1640培养基于37℃，体积分数0．05C02条件下培养。方法：实验于2005-10／2006-01在南方医科大学生物技术学院分子免疫研究所完成。采用反转录聚合酶链反应检测重组激活基因1，重组激活基因2，非同源末端连接装置途径中的DNA修复因子Ku70／Ku80。以及末端脱氧核苷转移酶mRNA表达；采用巢式、半巢式聚合酶链反应、连接介导的聚合酶链反应等方法检测T细胞受体重排删除DNA环和T细胞受体B链重组信号序列两端的断裂点。了解参与V（D）J重排过程的基因表达和T细胞受体基因重排中间体的产生情况。主耍观察指标：重组激活基因、DNA修复因子Ku70／Ku80和末端脱氧核苷转移酶mRNA表达以及T细胞受体基因重排在人白血病和淋巴癌细胞株的发生情况。结果：反转录聚合酶链反应检测结果显示：重组激活基因1mRNA在4种T细胞株中均被检测到，在两种B细胞株和两种髓性白血病细胞株中未检测到；重组激活基因2和末端脱氧核苷转移酶mRNA表达仅在Jurkat，Molt-4和6T-CEM3种T细胞株中检测到，但在6T-CEM表达较弱；除HL-60细胞未检测到Ku80表达外，所有细胞株均检测到Ku70和Ku80表达。对4种T细胞株T细胞受体重排中间体检测结果表明：仅在Jurkat细胞中检测到DB2-J132 sjTRECs与DB25’端和3’Rss断点，表明Jurkat细胞发生T细胞受体基因重排。同时发现Jurkat TCR Dβ2-Jβ2重排删除环结合区具有明显的多样性特征。结论：重组激活基因可能与T细胞白血病具有更为密切的关系。Jurkat细胞有可能成为研究重组激活基因与T细胞淋巴性肿瘤的一个潜在的细胞模型。     

Effect of histone deacetylase inhibitor on proliferation of biliary tract cancer cell lines

AIM： To explore the effect of histone deacetylase inhibitor, trichostatin A （TSA） on the growth of biliary tract cancer cell lines （gallbladder carcinoma cell line and cholangiocarcinoma cell line） in vivo and in vitro, and to investigate the perspective of histone deacetylase inhibitor in its clinical application. METHODS： The survival rates of gallbladder carcinoma cell line （Mz-ChA-l cell line） and cholangiocarcinoma cell lines （QBC939, KMBC and OZ cell lines） treated with various doses of TSA were detected by methylthiazoy tetrazolium （MTT） assay. A nude mouse model of transplanted gallbladder carcinoma （Mz-ChA-l cell line） was successfully established, and changes in the growth of transplanted tumor after treated with TSA were measured. RESULTS： TSA could inhibit the proliferation of gallbladder carcinoma cell line （Mz-ChA-l cell line） and cholangiocarcinoma cell lines （QBC939, KMBC and OZ cell lines） in a dose-dependent manner. After the nude mouse model of transplanted gallbladder carcinoma （Mz- ChA-l cell line） was successfully established, the growth of cancer was inhibited in the model after treated with TSA. CONCLUSION： TSA can inhibit the growth of cholangiocarcinoma and gallbladder carcinoma cell lines in vitro and in vivo.     

Epidemiology of lower gastrointestinal bleeding in China: single-center series and systematic analysis of Chinese literature with 53,951 patients

Objectives: The epidemiology of lower gastrointestinal bleeding (LGIB) in Western populations has been reported; however, there are scant Asian reports. The aim of the present study was to determine the etiology of LGIB in a Chinese population by reporting a retrospective case series and a systematic analysis of Chinese literature. Methods: A large colonoscopy database in a tertiary endoscopic center was searched to identify all patients with the indication of LGIB. The data, including patients' sex, age, endoscopic and pathological findings, were collected and analyzed. A comprehensive database search of the Chinese literature was carried out to obtain all relevant studies. Results: In our series, a total of 720 patients with LGIB were included. There were 425 males and 295 females with a median age of 50 years, the most common etiologies of LGIB were inflammatory bowel disease (IBD; 30.2%), polyps (23.4%) and cancer (10.7%). In 30.2% of all the patients, no obvious causes were identified. A systematic analysis of Chinese literature found an additional 160 studies providing relevant data in 53 951 patients. Overall, colorectal cancer (24.4%), colorectal polyps (24.1%), colitis (16.8%), anorectal disease (9.8%) and IBD (9.5%) were the most common etiologies of LGIB. The main etiologies were different between adults, the elderly and children. Conclusion: The study shows colorectal cancer, colorectal polyps, colitis, anorectal disease and IBD were the most common etiologies of LGIB in the Chinese adult and elderly population, whereas colorectal polyps, chronic colitis and intussusception were the main causes of LGIB in Chinese children. Whereas diverticulum, the most common cause of LGIB in Western populations, is uncommon in China.     

Epigenetic regulation of B cells and its role in autoimmune pathogenesis

B cells play a pivotal role in the pathogenesis of autoimmune diseases. Although previous studies have shown many genetic polymorphisms associated with B-cell activation in patients with various autoimmune disorders, progress in epigenetic research has revealed new mechanisms leading to B-cell hyperactivation. Epigenetic mechanisms, including those involving histone modifications, DNA methylation, and noncoding RNAs, regulate B-cell responses, and their dysregulation can contribute to the pathogenesis of autoimmune diseases. Patients with autoimmune diseases show epigenetic alterations that lead to the initiation and perpetuation of autoimmune inflammation. Moreover, many clinical and animal model studies have shown the promising potential of epigenetic therapies for patients. In this review, we present an up-to-date overview of epigenetic mechanisms with a focus on their roles in regulating functional B-cell subsets. Furthermore, we discuss epigenetic dysregulation in B cells and highlight its contribution to the development of autoimmune diseases. Based on clinical and preclinical evidence, we discuss novel epigenetic biomarkers and therapies for patients with autoimmune disorders.     

IL-24 Contributes to Neutrophilic Asthma in an IL-17A-Dependent Manner and Is Suppressed by IL-37

PurposeNeutrophilic asthma is associated with asthma exacerbation, steroid insensitivity, and severe asthma. Interleukin (IL)-24 is overexpressed in asthma and is involved in the pathogenesis of several allergic inflammatory diseases. However, the role and specific mechanism of IL-24 in neutrophilic asthma are unclear. We aimed to elucidate the roles of IL-24 and IL-37 in neutrophilic asthma, the relationships with IL-17A and the mechanisms regulating neutrophilic asthma progression.MethodsPurified human neutrophils were isolated from healthy volunteers, and a cell coculture system was used to evaluate the function of IL-24 in epithelium-derived IL-17A-dependent neutrophil migration. IL-37 or a small interfering RNA (siRNA) targeting IL-24 was delivered intranasally to verify the effect in a murine model of house dust mite (HDM)/lipopolysaccharide (LPS)-induced neutrophilic asthma.ResultsIL-24 enhanced IL-17A production in bronchial epithelial cells via the STAT3 and ERK1/2 signaling pathways; this effect was reversed by exogenous IL-37. Anti-IL-17A monoclonal antibodies reduced neutrophil chemotaxis induced by IL-24-treated epithelial cells in vitro. Increased IL-24 and IL-17A expression in the airway epithelium was observed in HDM/LPS-induced neutrophilic asthma. IL-37 administration or IL-24 silencing attenuated neutrophilic asthma, reducing IL-17A levels and decreasing neutrophil airway infiltration, airway hyperresponsiveness, and goblet cell metaplasia. Silencing IL-24 inhibited T-helper 17 (Th17) immune responses, but not Th1 or Th2 immune responses, in the lungs of a neutrophilic asthma model.ConclusionsIL-24 aggravated neutrophilic airway inflammation by increasing epithelium-derived IL-17A production, which could be suppressed by IL-37. Targeting the IL-24/IL-17A signaling axis is a potential strategy, and IL-37 is a potential candidate agent for alleviating neutrophilic airway inflammation in asthma.     

肾移植受者血清抗血管内皮细胞特异性抗体的提取和纯化

目的  探讨肾移植术后出现排斥反应的受者血清中抗血管内皮细胞特异性抗体的提取和纯化方法。方法  首先分离培养人脐静脉血管内皮细胞(HUVEC)。收集肾移植术后肾功能不良受者的血清样本, 应用流式细胞术进行抗血管内皮细胞特异性抗体的筛选; 用Luminex抗体检测平台检测血清中抗人类白细胞抗原(HLA)和主要组织相容性复合体Ⅰ类相关链A (MICA)的抗体。在确定血清标本中存在有抗血管内皮细胞特异性抗体后, 用HUVEC将其吸附。洗涤细胞后再将吸附的抗体从细胞膜上洗脱下来, 再用Protein-A/G磁珠再次纯化和浓缩洗脱液中的抗体IgG。采用流式细胞术检测洗脱液中抗体活性, 用SDS-聚丙烯酰胺凝胶(SDS-PAGE)凝胶和免疫印迹法鉴定纯化的抗血管内皮细胞特异性抗体(IgG)。结果  在386例肾移植受者的血清中, 选取血清肌酐(Scr)>400 μmoI/L、抗HLA抗体阴性、抗MICA抗体阴性和荧光反应强度(MFI)>16的5例受者的血清样本, 纯化后的抗血管内皮细胞特异性抗体IgG在SDS-PAGE凝胶显示免疫球蛋白重链(纯度>95%)。流式细胞术结果显示纯化的抗体具有重新结合血管内皮细胞表面抗原的特性。结论  采用人脐静脉血管内皮细胞吸附肾移植受者血清中抗血管内皮细胞特异性抗体的提纯方法可取得较好效果。     

PRRX1 promotes colorectal cancer stemness and chemoresistance via the JAK2/STAT3 axis by targeting IL-6

BackgroundStemness acquirement is one of the hallmarks of cancer and the major reason for the chemoresistance and poor prognosis of colorectal cancer (CRC). Previous research has revealed the stimulatory role of paired related homeobox 1 (PRRX1) on CRC metastasis. However, the role of PRRX1 in stemness acquirement and chemoresistance of CRC is still not clear.MethodsA retrospective cohort study was performed to investigate the relationship between PRRX1 expression and multiple clinicopathological characteristics of CRC patients. The functional effects of PRRX1 on stemness and chemoresistance of CRC cells were validated by in vitro and in vivo assays. Gene set enrichment analysis (GSEA) and JASPAR software were performed to predict the underlying mechanisms. Enzyme-linked immunosorbent assay (ELISA), Western blot, immunofluorescence, and dual-luciferase reporter assays were used to confirm the PRRX1-mediated signaling and its downstream factors.ResultsThe expression of PRRX1 was up-regulated in CRC tissues and cell lines compared to normal epithelial tissues and cell lines. High expression of PRRX1 was tightly associated with the metastasis, chemoresistance, and poor prognosis of CRC patients. Additionally, PRRX1 significantly promoted the proliferation, viability, stemness, and chemoresistance of CRC cells, as well as the activation of the interleukin-6 (IL-6)/JAK2/STAT3 axis. Inhibiting the expression of IL-6 dramatically eliminated the effects of PRRX1 on CRC cell stemness and chemoresistance.ConclusionsPRRX1 plays a vital role in the stemness and chemoresistance of CRC cells via JAK2/STAT3 signaling by targeting IL-6. Further, PRRX1 may be a valid biomarker for predicting the effect of chemotherapy and prognosis of CRC patients.     

An HGA-LSTM-Based Intelligent Model for Ore Pulp Density in the Hydrometallurgical Process

This study focused on the intelligent model for ore pulp density in the hydrometallurgical process. However, owing to the limitations of existing instruments and devices, the feed ore pulp density of thickener, a key hydrometallurgical equipment, cannot be accurately measured online. Therefore, aiming at the problem of accurately measuring the feed ore pulp density, we proposed a new intelligent model based on the long short-term memory (LSTM) and hybrid genetic algorithm (HGA). Specifically, the HGA refers to a novel optimization search algorithm model that can optimize the hyperparameters and improve the modeling performance of the LSTM. Finally, the proposed intelligent model was successfully applied to an actual thickener case in China. The intelligent model prediction results demonstrated that the hybrid model outperformed other models and satisfied the measurement accuracy requirements in the factory well.     

Effects of Solution Treatment on Damping Capacities of Binary Mg-X (X = Ga and Er) Alloys

Designing new materials for vibration and noise reduction that are lightweight is of great significance for industrial development. Magnesium (Mg) alloy is considered one of the best damping metal structural materials because of its low density, high specific strength, good energy storage characteristics and rich resources. Solution atoms have an important effect on the damping capacities of Mg alloys, but the relevant laws have not been completely clarified. In this work, two kinds of alloying elements (Ga and Er) with various atomic sizes were selected to study the metallographic structure and damping capacities of binary Mg-X (X = Ga and Er) alloys in the as-cast and solid solution states, respectively. Solution treatment can improve the damping capacities of binary Mg-X (X = Ga and Er) alloys, and the damping mechanisms of the two solid solution alloys are consistent with the G-L damping mechanism. The influence of alloy elements with different atomic sizes on damping capacities is also different. This influence is due to the various radii of solute atoms and Mg atoms which can result in different degrees of lattice distortion. This work provides a research basis for development and design of high-performance damping Mg alloy materials.     

Nitrogen-Doped Porous Carbon from Biomass with Efficient Toluene Adsorption and Superior Catalytic Performance

The chemical composition and surface groups of the carbon support affect the adsorption capacity of toluene. To investigate the effect of catalyst substrate on the catalytic performance, two different plant biomasses, banana peel and sugarcane peel, were used as carbon precursors to prepare porous carbon catalyst supports (Cba, Csu, respectively) by a chemical activation method. After decorating PtCo₃ nanoparticles onto both carbon supports (Cba, Csu), the PtCo₃-su catalyst demonstrated better catalytic performance for toluene oxidation (T₁₀₀ = 237 °C) at a high space velocity of 12,000 h⁻¹. The Csu support possessed a stronger adsorption capacity of toluene (542 mg g⁻¹), resulting from the synergistic effect of micropore volume and nitrogen-containing functional groups, which led to the PtCo₃-su catalyst exhibiting a better catalytic performance. Moreover, the PtCo₃-su catalyst also showed excellent stability, good water resistance properties, and high recyclability, which can be used as a promising candidate for practical toluene catalytic combustion.